WO2009063417A1

WO2009063417A1 - Power save mode transition for wireless networks

Info

Publication number: WO2009063417A1
Application number: PCT/IB2008/054750
Authority: WO
Inventors: Janne Marin; Harri Paloheimo; Jarkko Kneckt
Original assignee: Nokia Corporation; Nokia Inc.
Priority date: 2007-11-16
Filing date: 2008-11-12
Publication date: 2009-05-22

Abstract

Various embodiments are disclosed relating to wireless networks. According to an example embodiment, a technique is provided for transitioning from a full power mode to a power save mode in a wireless network. The technique may include sending (210) a request message from a requesting wireless node to one or more neighbor wireless nodes to request permission for the requesting wireless node to operate in a power save mode, and transitioning (220), by the requesting wireless node, from a full power mode to a power save mode after receiving an approve message from each of the one or more neighbor wireless nodes to which a request message was sent, each approve message providing approval from a sending wireless node for the requesting wireless node to operate in a power save mode.

Description

POWER SAVE MODE TRANSITION FOR WIRELESS NETWORKS

Inventors:

Janne Marin,

Harri Paloheimo,

Jarkko Kneckt

PRIORITY CLAIM

[0001 ] This application claims the benefit of priority based on United States Provisional Application No. 60/988,598, filed on November 16, 2007, entitled, "Power Save Mode Transition for Wireless Networks," the disclosure of which is hereby incorporated by reference.

BACKGROUND

[0002] In wireless networks, some wireless nodes may operate in either full power mode, or a power save (or low power) mode. For example, some types of wireless nodes may be operating on battery or a limited power source. During normal operation, a wireless node may typically operate in a full power mode, which allows the node to perform all normal functions. During certain periods, e.g., periods of inactivity, a wireless node may transition to the power save mode. While operating in the power save mode, the wireless node may consume significantly less power than in full power mode, but also provide very limited (if any) functionality since many components for the node may be powered off (for example) in power save mode.

[0003] For example, "IEEE P802.1 ls/D0.02, Draft Amendment to Standard for Information Technology - Telecommunications and Information Exchange Between Systems - LAN/MAN Specific Requirements - Part 11 : Wireless Medium Access Control (MAC) and physical layer (PHY) specifications: Amendment: ESS Mesh Networking" June 2006 ("IEEE P802.1 ls/D0.02"), allows mesh points to transition to a power save mode. See, e.g., IEEE P802.11s/D0.02, sec. 11A.13.3. However, when one or more wireless nodes transition to power save mode, this may have significant negative effects on the operation of the network, such as interrupting or preventing the forwarding of traffic that has been forwarded to the node that is now in a power save mode.

SUMMARY

[0004] According to an example embodiment, a method of transitioning from a full power mode to a power save mode in a wireless network may include sending a request message from a requesting wireless node to one or more neighbor wireless nodes to request permission for the requesting wireless node to operate in a power save mode, and transitioning, by the requesting wireless node, from a full power mode to a power save mode after receiving an approve message from each of the one or more neighbor wireless nodes to which a request message was sent, each approve message providing approval from a sending wireless node for the requesting wireless node to operate in a power save mode.

[0005] According to another example embodiment, an apparatus may include a controller, a memory coupled to the controller, a wireless transceiver coupled to the controller. The apparatus may be adapted to send a request message from a requesting wireless node to one or more neighbor wireless nodes to request permission for the requesting wireless node to operate in a power save mode, and transition, by the requesting wireless node, from a full power mode to a power save mode after receiving an approve message from each of the one or more neighbor wireless nodes to which a request message was sent, each approve message providing approval from a sending wireless node for the requesting wireless node to operate in a power save mode.

[0006] A method of transitioning from a full power mode to a power save mode in a wireless network may include sending a request message from a requesting wireless node to one or more neighbor wireless nodes to request permission for the requesting wireless node to operate in a power save mode, and transitioning, by the requesting wireless node, from a full power mode to a power save mode after receiving an approve message from a selected number or a selected percent of the one or more neighbor wireless nodes to which a request message was sent, each approve message providing approval from a sending wireless node for the requesting wireless node to operate in a power save mode.

[0007] A method of transitioning from a full power mode to a power save mode in a wireless network may include sending a request message from a requesting wireless node to one or more neighbor wireless nodes to request permission for the requesting wireless node to operate in a power save mode, starting a timer upon the sending a request message to one or more neighbor wireless nodes, and transitioning, by the requesting wireless node, from a full power mode to a power save mode after expiration of the timer.

[0008] A method of transitioning from a full power mode to a power save mode in a wireless network may include sending a request message from a requesting wireless node to one or more neighbor wireless nodes to request permission for the requesting wireless node to operate in a power save mode, and transitioning, by the requesting wireless node, from a full power mode to a power save mode after one of the following conditions occurs: 1) receiving an approve message from each (or a selected percent or a selected number) of the one or more neighbor wireless nodes to which a request message was sent, each approve message providing approval from a sending wireless node for the requesting wireless node to operate in a power save mode, or 2) expiration of a timer started upon the sending of a request message to one or more neighbor wireless nodes, whichever occurs first.

[0009] According to another example embodiment, an apparatus may include a controller, a memory coupled to the controller, a wireless transceiver coupled to the controller. The apparatus may be adapted to send a request message from a requesting wireless node to one or more neighbor wireless nodes to request permission for the requesting wireless node to operate in a power save mode, and transition, by the requesting wireless node, from a full power mode to a power save mode after one of the following conditions occurs: 1) receiving an approve message from each (or a selected percent or a selected number) of the one or more neighbor wireless nodes to which a request message was sent, each approve message providing approval from a sending wireless node for the requesting wireless node to operate in a power save mode, or 2) expiration of a timer started upon the sending of a request message to one or more neighbor wireless nodes, whichever occurs first.

[0010] In another example embodiment a method may include receiving a request message from a requesting wireless node requesting permission for the requesting wireless node to operate in a power save mode, sending one or more packets to be forwarded along a current forwarding path that includes the requesting wireless node, and sending an approve message to the requesting node after the sending one or more packets.

[0011] According to another example embodiment, a method may include receiving a request message from a requesting wireless node requesting permission for the requesting wireless node to operate in a power save mode, determining, in response to the receiving, a new forwarding path that does not include the requesting wireless node, and sending an approve message to the requesting wireless node after determining the new forwarding path.

[0012] According to yet another example embodiment, a method may include receiving a request message from a requesting wireless node requesting permission for the requesting wireless node to operate in a power save mode, the request message associated with a timer, determining, in response to the receiving, a new forwarding path that does not include the requesting wireless node, sending one or more packets to be forwarded along a current forwarding path that includes the requesting wireless node up until expiration of the timer, and discontinuing use of the current forwarding path to forward or send data not substantially later than expiration of the timer. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Example embodiments are illustrated in referenced figures of the drawings. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than restrictive.

[0014] FIG. 1 is a diagram illustrating a wireless network according to an example embodiment;

[0015] FIG. 2 is a flow chart illustrating operation of a wireless node according to an example embodiment.

[0016] FIG. 3 is a flow chart illustrating operation of a wireless node according to another example embodiment.

[0017] FIG. 4 is a flow chart illustrating operation of a wireless node according to an example embodiment.

[0018] FIG. 5 is a flow chart illustrating operation of a wireless node according to another example embodiment.

[0019] FIG. 6 is a flow chart illustrating operation of a wireless node according to another example embodiment.

[0020] FIG. 7 is a flow chart illustrating operation of a wireless node according to another example embodiment.

[0021] FIG. 8 is a flow chart illustrating operation of a wireless node according to yet another example embodiment.

[0022] FIG. 9 is a block diagram illustrating a wireless node according to an example embodiment.

[0023] FIG. 10 is a timing diagram illustrating operation of a wireless node according to an example embodiment.

[0024] FIG. 11 is a timing diagram illustrating operation of a wireless node according to another example embodiment. DETAILED DESCRIPTION

[0025] Referring to the Figures in which like numerals indicate like elements, FIG. 1 is a block diagram illustrating a wireless network according to an example embodiment. Wireless network 102 may include a number of wireless nodes such as one or more wireless infrastructure nodes (INs), including infrastructure node (IN) 103, IN 104 and IN 105. Each IN may be or may include an access point (AP), a base station (BS), a relay station or relay node, a node B, a mesh point, or other wireless node. One or more of the INs (such as IN 104) may be coupled to a fixed or wired network 110, which may be a LAN (local area network), the Internet, etc. For example, IN 104 and IN 105 may be coupled to network 110.

[0026] Wireless network 102 may also include one or more other wireless nodes, such as wireless nodes (or mobile nodes, MN) 107, 106, 108, 109, etc. Wireless nodes 107, 106, 108 and 109 may each be or include a mobile node, a subscriber station, a cellular phone, a wireless personal digital assistant (PDA), or other wireless device, a Wireless Local Area Network (WLAN) wireless device, a WiMAX device, or other wireless node or device. INs 103, 104 and 105 may be static, or may be mobile (ability to move).

[0027] In an example embodiment, MN 109 may be in communication with or associated with IN 103, MNs 106 and 107 may be in communication with or associated with IN 104, and MN 109 may be in communication with or associated with IN 105. This is merely an example embodiment, and other arrangements or configurations may be provided.

[0028] According to such an example embodiment, network 102 may be a wireless mesh network which may include a collection of mesh points (MPs) interconnected via wireless communication links. For example, INs 103, 104 and 105 may each be mesh points in wireless communication with each other (and possibly other wireless nodes. Thus, a group of INs may be in wireless communication with each other, and may create a mesh or network of nodes to allow traffic to be forwarded between a traffic source and destination. Such traffic may travel or be forwarded via one or more INs 103, 104, 105, etc. (or mesh points) towards a destination. For example, traffic originated by MN 107 may be forwarded by IN 103 to IN 104 to a destination via network 110. This is merely one example embodiment.

[0029] Each IN (or MP) may also be static (or fixed in location) or may be mobile or be capable of being moved or movable, and may be capable of dynamically reconfiguring itself, although the disclosure is not limited thereto.

[0030] The various embodiments described herein may be applicable to a wide variety of networks and technologies, such as WLAN networks (e.g., IEEE 802.11 type networks), IEEE 802.16 WiMAX networks, WiMedia networks, Ultra Wide Band networks, cellular networks, radio networks, or other wireless networks. In another example embodiment, the various examples and embodiments may be applied, for example, to a mesh wireless network, where a plurality of mesh points (e.g., Access Points) may be coupled together via wired or wireless links. The various embodiments described herein may be applied to wireless networks, both in an infrastructure mode where an AP or base station may communicate with a station (e.g., communication occurs through APs), as well as an ad-hoc mode in which wireless stations may communicate directly via a peer-to-peer network, for example.

[0031] The term "wireless node" or "node," or the like, may include, for example, a wireless station, such as a mobile station or subscriber station, an access point (AP) or base station, a relay station, an infrastructure node, node B, a wireless personal digital assistant (PDA), a cell phone, an 802.11 WLAN phone, a WiMedia device, a WiMAX device, a wireless mesh point (MP), or any other wireless device. These are merely a few examples of the wireless devices and technologies that may be used to implement the various embodiments described herein, and this disclosure is not limited thereto.

[0032] Referring to FIG. 1 again, IN 103 may include a buffer 112 to store packets to be forwarded. For example, for each destination address (e.g., destination address identified in a packet), IN 103 may store a current forwarding path that may identify an IN (or other node) as the next hop for forwarding the packet to its intended destination, for example. For example, a data packet may be received at IN 103 from MN 107 via link 113. The current forwarding path used by IN 103 may identify IN 104 as the next hop in a forwarding path for this packet. Thus, IN 103 may forward the packet to IN 104 via link 115. IN may then forward the received packet on via network 110, for example. A problem may arise where IN 104 suddenly transitions from a full power mode to a power save mode. If that happens, in some cases, IN 103 (and other INs or nodes), may not (initially) be aware of the transition by IN 104 to power save mode, and thus, IN 103 may continue to forward packets to IN 104 for forwarding. However, with IN 104 in power save mode, the packets will not be received or forwarded by IN 104, and these packets may typically need to be retransmitted, which can be very inefficient. IN 103 may eventually determine or obtain a new data forwarding path that replaces IN 104 with another node, but there may be significant delay and loss of packets, at least in some cases.

[0033] FIG. 10 is a timing diagram illustrating operation of a wireless node according to an example embodiment. Initially, IN 104 may be operating in full power mode, but determines that it would like to transition to power save mode. For example, if IN 104 has forwarded all the data (or at least all the high priority traffic) in its data buffers, it may then want to transition to power save mode to conserve battery power, for example. In an example embodiment, IN 104 may send a request message to one or more (or even all) neighbor wireless nodes to request permission for the requesting wireless node (IN 104 in this example) to operate in a power save mode. Each request message may be a unicast frame or message, or an acknowledged multicast frame may be sent to multiple neighbor nodes, for example. In an example embodiment, IN 104 may then transition from full power mode to a power save mode after receiving an approve message (or an acknowledgement to the multicast request frame if a multicast request frame is sent) from each of the neighbor wireless nodes to which a request message was sent. Each approve message may provide permission or approval from a sending neighbor wireless node for the requesting wireless node to operate in a power save mode.

[0034] For example, as shown in FIG. 10, IN 104 may send a request message 1004 to IN 103. Upon receiving the request message 1004, at 1006, IN 103 may prepare for IN 104 to transition to a power save mode, e.g., by (for example, immediately) forwarding traffic (or some or all packets) in its data buffers to IN 104 (the requesting wireless node), and determining a new forwarding path that does not include the requesting node (IN 104). These two functions, forwarding data and determining a new forwarding path may be performed in any order, and may be performed in parallel, for example. Other functions or tasks may be performed as well. IN 103 may forward data or packets to IN 104 before IN 104 enters power save mode, to ensure (or at least increase the likelihood) that such packets will be received and forwarded.

[0035] Also, IN 103 may determine a forwarding path that may replace IN 104 with another node. For example, a current forwarding path (used by IN 103) that includes IN 104 may be updated by IN 103 to replace IN 104 with another wireless node, such as IN 105. IN 103 may determine a new forwarding path by calculating the new forwarding path, by requesting and obtaining the forwarding path from one or more other wireless nodes, or other technique. Determining the new forwarding path may include, for example, determining a new wireless node to replace the requesting wireless node for the forwarding path. For example, IN 103 may determine a new forwarding path that replaces IN 104 with IN 105. For example, after IN 103 determines a new forwarding path, traffic directed to network 110 (FIG. 1) from IN 103, may now be forwarded to IN 105 instead of IN 104.

[0036] In an example embodiment, after IN 103 is prepared for he transition for IN 104 to a power save mode, IN 103 may send an approve message 1010 to IN 104. This approve message may provide permission from IN 103 for IN 104 to operate in a power save mode. IN 103 may begin using the new forwarding path (e.g., forwarding data to IN 105 instead of to IN 104), e.g., before sending approve message 1010, or not substantially later than sending the approve message. This is because, upon receiving the approve message from IN 103 (and possibly other neighbor wireless nodes), IN 104 may transition to power save mode.

[0037] As shown in FIG. 10, the requesting node (IN 104) may similarly send a request message to other neighbor wireless nodes, such as sending a request message 1012 to IN 105. IN 105, at 1014, may similarly prepare for the transition of IN 104 to a power save mode by forwarding data in buffers to IN 104, determining a new forwarding path, etc. These other neighbor wireless nodes, such as IN 105, may then send an approve message (such as approve message 1018 from IN 105) and use the new forwarding path at 1016 that does not include the requesting node (since the requesting node will not be available to forward traffic after it transitions to power save mode). Although not shown in FIG. 10, the request messages may be sent out together or very close together in time.

[0038] In an example embodiment, the requesting wireless node (IN 104 in this example) may transition at 1020 to power save mode after receiving an approve message from each (or from all) of the neighbor wireless nodes to which a request message was sent (in this example, after receiving an approve message 1010 from IN 103 and an approve message 1018 from IN 105). For, example, this may ensure that all (or at least some) neighbor wireless nodes have prepared for the transition, e.g., by determining a new forwarding path, and this may decrease the risk that packets may be dropped due to the transition of the requesting node to power save mode. The requesting node (IN 104) may remain in full power mode from the time 1002 of sending out request message(s), until receiving approval from one or more or even all of the neighbor wireless nodes.

[0039] In another example embodiment with reference to FIG. 10, a neighbor wireless node may determine, in response to receiving a request message, a new forwarding path that does not include the requesting wireless node, send one or more packets to be forwarded along a current forwarding path that includes the requesting wireless node (e.g., send data to the requesting node before sending the approve message), and discontinuing use of the current forwarding path and beginning to use the new forwarding path to forward or send data not substantially later than sending of the approve message to the requesting node.

[0040] In another example embodiment, a requesting wireless node may transition to a power save mode if the requesting wireless node has received an approve message from a selected number or selected percent of the one or more wireless nodes to which a request message was sent. For example, the requesting node may transition to a power save mode if 75% or more of the neighbor wireless nodes to which a request message was sent replied with an approve message. [0041] Referring to FIG. 10, at 1021, IN 104 may transition to a full power mode after being in a power save mode for a period of time, for example. IN 104 may send a full power notification message to one or more (or even all) of the neighbor wireless nodes, to notify the neighbor wireless nodes that IN 104 is now in full power mode. Alternatively, the full power notification message may provide a time (or time period) at which IN 104 will be in full power mode. The full power notification message may be sent as a unicast, broadcast or multicast message, as examples. In response to the full power notification message, one or more (or even all) of the neighbor wireless nodes may determine a new or updated forwarding path that may now include IN 104 (again), and may begin using such new or updated forwarding path either immediately (in case where notification message indicates that IN 104 is now in full power mode) or at a time indicated by the full power notification message, or may send data frames to IN 104 before such indicated time, assuming that such frames will (likely) reach IN 104 after IN 104 transitions to full power mode. Thus, after IN 104 transitions back to full power mode, one or more neighbor wireless nodes may then resume forwarding frames to (or through) IN 104.

[0042] FIG. 11 is a timing diagram illustrating operation of a wireless node according to another example embodiment. In FIG. 11, rather than conditioning a transition to a power save mode on receiving approval from one or more (or even all) of the neighbor wireless nodes to which a request was sent, a requesting wireless node may transition to a power save mode after expiration of a timer that may have been started upon the transmission of one or more request messages to the neighbor wireless nodes. In this example embodiment, each neighbor wireless node may typically send an acknowledgement back to the requesting node upon receipt of the request message, even if the neighbor wireless node is not yet ready for the transition of the requesting wireless node to a power save mode. Thus, in an example embodiment, such an acknowledgement message may merely acknowledge receipt of the request message, and not provide approval for transition to power save mode. The timer may provide each (or one or more) neighbor wireless nodes with a period of time (e.g., a known period of time) before the requesting wireless node will transition to power save mode. This period of time, may, in some cases allow one or more nodes to prepare for the transition. However, even if one or more of the neighbor nodes are not prepared for the transition, the requesting node may transition anyway once the timer expires, for example. In this manner, the transition to power save mode will not be unnecessarily delayed an undetermined period of time due to failure by one or more neighbor nodes to send an approval message, for example. However, this comes at the price (or trade off) of possibly greater likelihood that one or more wireless nodes may not be prepared for the transition to power save mode.

[0043] As shown in FIG. 11, IN 104 (the requesting node in this example) may be in full power mode at 1102 and may send a request message 1104 (e.g., as a unicast frame) to IN 103. Upon sending the request message, the requesting node (IN 104) may start a timer (or start a timer initialized to a timer value). IN 104 may send a request message 1104 to IN 103, and send a request message 1106 to IN 105, for example. The timer value may be known in advance by neighbor wireless nodes In 103 and IN 105, such as broadcast in beacon frame, or transmitted from a central node, or other mechanism for communicating the timer value. Alternatively, the request message may identify the timer value. A same timer value may be used for each request message. Or, slightly different timer values may be used for each request message. For example, if there is a delay between sending request message 1104 and sending request message 1106, then the timer value identified in request message 1106 may identify a shorter period of time (to account for lapsed time between messages) than the timer value in request message 1104, although this is not required.

[0044] IN 103 may receive the request message 1104 and may send an ACK (acknowledgement) message 1108 to IN 104 to acknowledge receipt of the request message. Likewise, IN 105 may receive the request message 1106 and send an ACK message 1110 to IN 104. Each neighbor nodes 103 and 105 may attempt to prepare at 109 for the transition of IN 104 to power save mode before expiration of the timer, e.g., forward traffic in data buffers to IN 104, determine a new forwarding path that does not include the requesting node (or replaces the requesting node with another wireless node). Neighbor wireless nodes IN 103 and IN 105 may each begin at 1112 using their new forwarding path before, or not substantially later than, expiration of the timer, for example.

[0045] The requesting wireless node (e.g., IN 104) may transition at 1116 to a power save mode upon or after expiration of the timer at 1114. Since transition is not conditioned upon approval from neighbor nodes, it is possible that the requesting wireless node may transition to a power save mode before the neighbor nodes are prepared (e.g., before they have determined a new forwarding path or performed other preparations for the transition).

[0046] Although not shown in FIG. 11, similar to FIG. 10, IN 104 may transition to a full power mode after being in a power save mode for a period of time, for example. IN 104 may send a full power notification message to one or more (or even all) of the neighbor wireless nodes, to notify the neighbor wireless nodes that IN 104 is now in full power mode, or will be in full power mode at a future time or time period. In response to the full power notification message, one or more (or even all) of the neighbor wireless nodes may determine a new or updated forwarding path that may now include IN 104 (e.g., again), and may begin using such new or updated forwarding path either immediately (in case where notification message indicates that IN 104 is now in full power mode) or at a time indicated by the full power notification message, for example. Thus, after IN 104 transitions back to full power mode, one or more neighbor wireless nodes may then resume forwarding frames to IN 104.

[0047] In yet another example embodiment, the approval feature of FIG. 10 and the timer feature of FIG. 11 may be combined. For example, the requesting wireless node may send a request message to one or more wireless nodes, and start a timer upon transmission of one or more request messages. The requesting node may, in an example embodiment, transition to a power save mode after one of the following conditions occurs (whichever occurs first): 1) receiving an approve message from each (or a selected percent or a selected number) of the one or more neighbor wireless nodes to which a request message was sent, each approve message providing approval from a sending wireless node for the requesting wireless node to operate in a power save mode, or 2) expiration of a timer started upon the sending of a request message to one or more neighbor wireless nodes.

[0048] FIG. 2 is a flow chart illustrating operation of a wireless node according to an example embodiment. The flow chart in FIG. 2 may illustrate a method of transitioning from a full power mode to a power save mode in a wireless network. Operation 210 may include a wireless node (e.g., mesh point) sending a request message from a requesting wireless node to one or more neighbor wireless nodes to request permission for the requesting wireless node to operate in a power save mode. Operation 220 may include transitioning, by the requesting wireless node, from a full power mode to a power save mode after receiving an approve message from each of the one or more neighbor wireless nodes to which a request message was sent, each approve message providing approval from a sending wireless node for the requesting wireless node to operate in a power save mode. Various alternative embodiments will be described with reference to FIG. 2.

[0049] The flow chart of FIG. 2 may further include transitioning, by the requesting wireless node, from the power save mode back to the full power mode; and sending a full power notification message to one or more of the neighbor wireless nodes indicating that the requesting node is in full power mode.

[0050] The flow chart of FIG. 2 may further include sending a full power notification message to one or more of the neighbor wireless nodes indicating a time at which the requesting node will be in full power mode; and transitioning, by the requesting wireless node, from the power save mode back to the full power mode at the indicated time.

[0051] The flow chart of FIG. 2 may further include the requesting wireless node, after sending the request message to one or more wireless neighbor nodes, continuing to operate in a full power mode until receiving an approve message from each of the one or more neighbor wireless nodes to which a request message was sent.

[0052] The flow chart of FIG. 2 may further include the requesting wireless node, after sending the request message to one or more wireless neighbor nodes, continuing to operate, including receiving and forwarding packets, in a full power mode until receiving an approve message from each of the one or more neighbor wireless nodes to which a request message was sent.

[0053] The flow chart of FIG. 2 wherein, at the time of sending a request message to a neighbor wireless node, the neighbor wireless node is using the requesting wireless node in a forwarding path to forward packets.

[0054] According to another example embodiment, an apparatus may include a controller, a memory coupled to the controller, a wireless transceiver coupled to the controller. The apparatus may be adapted to send a request message from a requesting wireless node to one or more neighbor wireless nodes to request permission for the requesting wireless node to operate in a power save mode, and transition, by the requesting wireless node, from a full power mode to a power save mode after receiving an approve message from each of the one or more neighbor wireless nodes to which a request message was sent, each approve message providing approval from a sending wireless node for the requesting wireless node to operate in a power save mode.

[0055] According to various example embodiments, the apparatus may include an infrastructure node, a mesh point, a relay station, a base station or access point. In an example embodiment, the neighbor wireless nodes may include, for example, neighbor mesh points, or peer mesh points.

[0056] FIG. 3 is a flow chart illustrating operation of a wireless node according to another example embodiment. The method of FIG. 3 may include a method of transitioning from a full power mode to a power save mode in a wireless network. Operation 310 may include sending a request message from a requesting wireless node to one or more neighbor wireless nodes to request permission for the requesting wireless node to operate in a power save mode. Operation 320 may include transitioning, by the requesting wireless node, from a full power mode to a power save mode after receiving an approve message from a selected number or a selected percent of the one or more neighbor wireless nodes to which a request message was sent, each approve message providing approval from a sending wireless node for the requesting wireless node to operate in a power save mode. [0057] FIG. 4 is a flow chart illustrating operation of a wireless node according to another example embodiment. The method of FIG. 4 may include a method of transitioning from a full power mode to a power save mode in a wireless network. Operation 410 may include sending a request message from a requesting wireless node to one or more neighbor wireless nodes to request permission for the requesting wireless node to operate in a power save mode. Operation 420 may include starting a timer upon the sending a request message to one or more neighbor wireless nodes. Operation 430 may include transitioning, by the requesting wireless node, from a full power mode to a power save mode after expiration of the timer.

[0058] In an example embodiment, the flow chart of FIG. 4 may further include sending a full power notification message to one or more of the neighbor wireless nodes; and transitioning, by the requesting wireless node, from the power save mode back to the full power mode.

[0059] In another example embodiment, operation 430 may include receiving an acknowledgement of receipt of the request message from each of the neighbor wireless nodes to which the request message was sent; and transitioning, by the requesting wireless node, from a full power mode to a power save mode after the receiving of the acknowledgement of receipt from each of the neighbor wireless nodes to which the request was sent and after expiration of the timer.

[0060] In another example embodiment of the flow chart of FIG. 4, a timer value for the timer may be known in advance by the one or more neighbor wireless nodes. In another example embodiment of the flow chart of FIG. 4, the request message indicates a timer value for the timer.

[0061] FIG. 5 is a flow chart illustrating operation of a wireless node according to another example embodiment. The method of FIG. 5 may include a method of transitioning from a full power mode to a power save mode in a wireless network. Operation 510 may include sending a request message from a requesting wireless node to one or more neighbor wireless nodes to request permission for the requesting wireless node to operate in a power save mode. Operation 520 may include transitioning, by the requesting wireless node, from a full power mode to a power save mode after one of the following conditions occurs: 1) receiving an approve message from each (or a selected percent or a selected number) of the one or more neighbor wireless nodes to which a request message was sent, each approve message providing approval from a sending wireless node for the requesting wireless node to operate in a power save mode, or 2) expiration of a timer started upon the sending of a request message to one or more neighbor wireless nodes, whichever occurs first.

[0062] The flow chart of FIG. 5 may further include sending a full power notification message to one or more of the neighbor wireless nodes; and transitioning, by the requesting wireless node, from the power save mode back to the full power mode.

[0063] According to another example embodiment, an apparatus may include a controller, a memory coupled to the controller, a wireless transceiver coupled to the controller. The apparatus may be adapted to send a request message from a requesting wireless node to one or more neighbor wireless nodes to request permission for the requesting wireless node to operate in a power save mode, and transition, by the requesting wireless node, from a full power mode to a power save mode after one of the following conditions occurs: 1) receiving an approve message from each (or a selected percent or a selected number) of the one or more neighbor wireless nodes to which a request message was sent, each approve message providing approval from a sending wireless node for the requesting wireless node to operate in a power save mode, or 2) expiration of a timer started upon the sending of a request message to one or more neighbor wireless nodes, whichever occurs first.

[0064] FIG. 6 is a flow chart illustrating operation of a wireless node according to another example embodiment. Operation 610 may include receiving a request message from a requesting wireless node requesting permission for the requesting wireless node to operate in a power save mode. Operation 620 may include sending one or more packets to be forwarded along a current forwarding path that includes the requesting wireless node. Operation 630 may include sending an approve message to the requesting node after the sending one or more packets.

[0065] The flow chart of FIG. 6 may further include determining a first new forwarding path that does not include the requesting wireless node; using the first new forwarding path to forward data frames; receiving a full power notification message from the requesting wireless node; determining a second new forwarding path that includes the requesting wireless node again; and using the second new forwarding path to forward data frames.

[0066] The flow chart of FIG. 6 may further include determining a new forwarding path that does not include the requesting wireless node.

[0067] The flow chart of FIG. 6 may further include determining a new forwarding path that replaces the requesting wireless node with another wireless node. The flow chart of FIG. 6 may further include determining a new packet forwarding path that does not include the requesting wireless node; and forwarding data via the new packet forwarding path.

[0068] The flow chart of FIG. 6 may further include determining a new forwarding path that replaces the requesting wireless node with another wireless node; and forwarding data via the new forwarding path.

[0069] In the flow chart of FIG. 6, operation 620 may include sending all packets stored in a buffer to be forwarded along the current forwarding path that includes the requesting wireless node.

[0070] The flow chart of FIG. 6 may further include determining, in response to the receiving, a new forwarding path that does not include the requesting wireless node; and wherein the sending one or more packets comprises: sending one or more packets to be forwarded along a current forwarding path that includes the requesting wireless node; and discontinuing use of the current forwarding path and beginning to use the new forwarding path to forward or send data not substantially later than sending of the approve message to the requesting wireless node.

[0071] FIG. 7 is a flow chart illustrating operation of a wireless node according to another example embodiment. Operation 710 may include receiving a request message from a requesting wireless node requesting permission for the requesting wireless node to operate in a power save mode. Operation 720 may include determining, in response to the receiving, a new forwarding path that does not include the requesting wireless node. Operation 730 may include sending an approve message to the requesting wireless node after determining the new forwarding path.

[0072] In an alternative embodiment, the flow chart of FIG. 7 may further include one or more additional operations, such as: using the new forwarding path to forward data frames; receiving a full power notification message from the requesting wireless node; determining a second new forwarding path that includes the requesting wireless node again; and using the second new forwarding path to forward data frames.

[0073] In an alternative embodiment, the flow chart of FIG. 7 may further include discontinuing use of a current forwarding path that includes the requesting wireless node and beginning to use the new forwarding path to forward or send data not substantially later than sending of the approve message to the requesting wireless node.

[0074] FIG. 8 is a flow chart illustrating operation of a wireless node according to another example embodiment. Operation 810 may include receiving a request message from a requesting wireless node requesting permission for the requesting wireless node to operate in a power save mode, the request message associated with a timer. Operation 820 may include determining, in response to the receiving, a new forwarding path that does not include the requesting wireless node. Operation 830 may include sending one or more packets to be forwarded along a current forwarding path that includes the requesting wireless node up until expiration of the timer. Operation 840 may include discontinuing use of the current forwarding path to forward or send data not substantially later than expiration of the timer.

[0075] In an alternative embodiment, the flow chart of FIG. 8 may further include one or more additional operations, such as: receiving a full power notification message from the requesting wireless node; determining a second new forwarding path that includes the requesting wireless node again; and using the second new forwarding path to forward data frames.

[0076] In an example embodiment, operation 830 may include sending one or more packets to the requesting wireless node up until expiration of the timer.

[0077] In an example embodiment, operation 810 may include receiving a request message from a requesting wireless node requesting permission for the requesting wireless node to operate in a power save mode, the request message associated with a timer, the request message identifying a value of the timer.

[0078] In an example embodiment, operation 810 may include receiving a request message from a requesting wireless node requesting permission for the requesting wireless node to operate in a power save mode, the request message associated with a timer, a value of the timer being previously provided.

[0079] In an example embodiment, the flow chart of FIG. 8 may further include using the new forwarding path to forward data.

[0080] In another example embodiment, operation 820 may include calculating a new forwarding path that does not include the requesting wireless node.

[0081] In another example embodiment, operation 820 may include requesting a new forwarding path from one or more other wireless nodes; and receiving the new forwarding path.

[0082] In another example embodiment, operation 820 may include determining a new forwarding path that replaces the requesting wireless node with another wireless node.

[0083] FIG. 9 is a block diagram illustrating an example apparatus 900 that may be provided in a wireless node according to an example embodiment. Each wireless node, such as a station, AP, MP, etc., may include, for example, a wireless transceiver 902 to transmit and receive signals, a controller 904 to control operation of the station or node and execute instructions or software, and a memory 906 to store data and/or instructions.

[0084] Controller 904 may be programmable and capable of executing software or other instructions stored in memory or on other computer media to perform the various tasks and functions described above, such as one or more the tasks or methods described above.

[0085] Implementations of the various techniques described herein may be implemented in digital electronic circuitry, or in computer hardware, firmware, software, or in combinations of them. Implementations may implemented as a computer program product, i.e., a computer program tangibly embodied in an information carrier, e.g., in a machine-readable storage device or in a propagated signal, for execution by, or to control the operation of, data processing apparatus, e.g., a programmable processor, a computer, or multiple computers. A computer program, such as the computer program(s) or methods described above, can be written in any form of programming language, including compiled or interpreted languages, and can be deployed in any form, including as a stand-alone program or as a module, component, subroutine, or other unit suitable for use in a computing environment. A computer program can be deployed to be executed on one computer or on multiple computers at one site or distributed across multiple sites and interconnected by a communication network.

[0086] Method steps may be performed by one or more programmable processors executing a computer program to perform functions by operating on input data and generating output. Method steps also may be performed by, and an apparatus may be implemented as, special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application- specific integrated circuit).

[0087] While a number of aspects and embodiments have been discussed above, it will be appreciated that various modifications, permutations, additions and/or sub- combinations of these aspects and embodiments are possible.

Claims

WHAT IS CLAIMED IS:

1. A method of transitioning from a full power mode to a power save mode in a wireless network, comprising: sending a request message from a requesting wireless node to one or more neighbor wireless nodes to request permission for the requesting wireless node to operate in a power save mode; and transitioning, by the requesting wireless node, from a full power mode to a power save mode after receiving an approve message from each of the one or more neighbor wireless nodes to which a request message was sent, each approve message providing approval from a sending wireless node for the requesting wireless node to operate in a power save mode.

2. The method of claim 1 and further comprising: transitioning, by the requesting wireless node, from the power save mode back to the full power mode; and sending a full power notification message to one or more of the neighbor wireless nodes indicating that the requesting node is in full power mode.

3. The method of claim 1 and further comprising: sending a full power notification message to one or more of the neighbor wireless nodes indicating a time at which the requesting node will be in full power mode; and transitioning, by the requesting wireless node, from the power save mode back to the full power mode at the indicated time.

4. The method of claim 1 and further comprising the requesting wireless node, after sending the request message to one or more wireless neighbor nodes, continuing to operate in a full power mode until receiving an approve message from each of the one or more neighbor wireless nodes to which a request message was sent.

5. The method of claim 1 and further comprising the requesting wireless node, after sending the request message to one or more wireless neighbor nodes, continuing to operate, including receiving and forwarding packets, in a full power mode until receiving an approve message from each of the one or more neighbor wireless nodes to which a request message was sent.

6. The method of claim 1 wherein, at the time of sending a request message to a neighbor wireless node, the neighbor wireless node is using the requesting wireless node in a forwarding path to forward packets.

7. An apparatus comprising: a controller; a memory coupled to the controller; and a wireless transceiver coupled to the controller; the apparatus being configured to: send a request message from a requesting wireless node to one or more neighbor wireless nodes to request permission for the requesting wireless node to operate in a power save mode; and transition, by the requesting wireless node, from a full power mode to a power save mode after receiving an approve message from each of the one or more neighbor wireless nodes to which a request message was sent, each approve message providing approval from a sending wireless node for the requesting wireless node to operate in a power save mode.

8. The apparatus of claim 7 wherein the apparatus comprises an infrastructure node.

9. The apparatus of claim 7 wherein the apparatus comprises a mesh point.

10. The apparatus of claim 7 wherein the apparatus comprises a relay station.

11. The apparatus of claim 7 wherein the apparatus comprises a base station or access point.

12. The apparatus of claim 7 wherein the neighbor wireless nodes comprises neighbor mesh points.

13. The apparatus of claim 7 wherein the neighbor wireless nodes comprises peer mesh points.

14. A method of transitioning from a full power mode to a power save mode in a wireless network, comprising: sending a request message from a requesting wireless node to one or more neighbor wireless nodes to request permission for the requesting wireless node to operate in a power save mode; and transitioning, by the requesting wireless node, from a full power mode to a power save mode after receiving an approve message from a selected number or a selected percent of the one or more neighbor wireless nodes to which a request message was sent, each approve message providing approval from a sending wireless node for the requesting wireless node to operate in a power save mode.

15. A method of transitioning from a full power mode to a power save mode in a wireless network, comprising: sending a request message from a requesting wireless node to one or more neighbor wireless nodes to request permission for the requesting wireless node to operate in a power save mode; starting a timer upon the sending a request message to one or more neighbor wireless nodes; and transitioning, by the requesting wireless node, from a full power mode to a power save mode after expiration of the timer.

16. The method of claim 15 and further comprising: sending a full power notification message to one or more of the neighbor wireless nodes; and transitioning, by the requesting wireless node, from the power save mode back to the full power mode.

17. The method of claim 15 wherein the transitioning comprises: receiving an acknowledgement of receipt of the request message from each of the neighbor wireless nodes to which the request message was sent; and transitioning, by the requesting wireless node, from a full power mode to a power save mode after the receiving of the acknowledgement of receipt from each of the neighbor wireless nodes to which the request was sent and after expiration of the timer.

18. The method of claim 15 wherein a timer value for the timer is known in advance by the one or more neighbor wireless nodes.

19. The method of claim 15 wherein the request message indicates a timer value for the timer.

20. A method of transitioning from a full power mode to a power save mode in a wireless network, comprising: sending a request message from a requesting wireless node to one or more neighbor wireless nodes to request permission for the requesting wireless node to operate in a power save mode; and transitioning, by the requesting wireless node, from a full power mode to a power save mode after one of the following conditions occurs:

1) receiving an approve message from each (or a selected percent or a selected number) of the one or more neighbor wireless nodes to which a request message was sent, each approve message providing approval from a sending wireless node for the requesting wireless node to operate in a power save mode; or 2) expiration of a timer started upon the sending of a request message to one or more neighbor wireless nodes, whichever occurs first.

21. The method of claim 20 and further comprising: sending a full power notification message to one or more of the neighbor wireless nodes; and transitioning, by the requesting wireless node, from the power save mode back to the full power mode.

22. An apparatus comprising: a controller; a memory coupled to the controller; and a wireless transceiver coupled to the controller; the apparatus configured to: send a request message from a requesting wireless node to one or more neighbor wireless nodes to request permission for the requesting wireless node to operate in a power save mode; and transition, by the requesting wireless node, from a full power mode to a power save mode after one of the following conditions occurs:

1) receiving an approve message from each (or a selected percent or a selected number) of the one or more neighbor wireless nodes to which a request message was sent, each approve message providing approval from a sending wireless node for the requesting wireless node to operate in a power save mode; or

2) expiration of a timer started upon the sending of a request message to one or more neighbor wireless nodes, whichever occurs first.

23. A method comprising: receiving a request message from a requesting wireless node requesting permission for the requesting wireless node to operate in a power save mode; sending one or more packets to be forwarded along a current forwarding path that includes the requesting wireless node; and sending an approve message to the requesting node after the sending one or more packets.

24. The method of claim 23 and further comprising: determining a first new forwarding path that does not include the requesting wireless node; using the first new forwarding path to forward data frames; receiving a full power notification message from the requesting wireless node; determining a second new forwarding path that includes the requesting wireless node again; and using the second new forwarding path to forward data frames.

25. The method of claim 23 and further comprising determining a new forwarding path that does not include the requesting wireless node.

26. The method of claim 23 and further comprising determining a new forwarding path that replaces the requesting wireless node with another wireless node.

27. The method of claim 23 and further comprising determining a new packet forwarding path that does not include the requesting wireless node; and forwarding data via the new packet forwarding path.

28. The method of claim 23 and further comprising: determining a new forwarding path that replaces the requesting wireless node with another wireless node; and forwarding data via the new forwarding path.

29. The method of claim 23 wherein the sending one or more packets comprises sending all packets stored in a buffer to be forwarded along the current forwarding path that includes the requesting wireless node.

30. The method of claim 23 and further comprising: determining, in response to the receiving, a new forwarding path that does not include the requesting wireless node; and wherein the sending one or more packets comprises: sending one or more packets to be forwarded along a current forwarding path that includes the requesting wireless node; and discontinuing use of the current forwarding path and beginning to use the new forwarding path to forward or send data not substantially later than sending of the approve message to the requesting wireless node.

31. A method comprising: receiving a request message from a requesting wireless node requesting permission for the requesting wireless node to operate in a power save mode; determining, in response to the receiving, a new forwarding path that does not include the requesting wireless node; and sending an approve message to the requesting wireless node after determining the new forwarding path.

32. The method of claim 31 and further comprising discontinuing use of a current forwarding path that includes the requesting wireless node and beginning to use the new forwarding path to forward or send data not substantially later than sending of the approve message to the requesting wireless node.

33. A method comprising : receiving a request message from a requesting wireless node requesting permission for the requesting wireless node to operate in a power save mode, the request message associated with a timer; determining, in response to the receiving, a new forwarding path that does not include the requesting wireless node; sending one or more packets to be forwarded along a current forwarding path that includes the requesting wireless node up until expiration of the timer; and discontinuing use of the current forwarding path to forward or send data not substantially later than expiration of the timer.

34. The method of claim 33 and further comprising: receiving a full power notification message from the requesting wireless node; determining a second new forwarding path that includes the requesting wireless node again; and using the second new forwarding path to forward or send data.

35. The method of claim 33 wherein the sending one or more packets comprises sending one or more packets to the requesting wireless node up until expiration of the timer.

36. The method of claim 33 wherein the receiving a request message comprises receiving a request message from a requesting wireless node requesting permission for the requesting wireless node to operate in a power save mode, the request message associated with a timer, the request message identifying a value of the timer.

37. The method of claim 33 wherein the receiving a request message comprises receiving a request message from a requesting wireless node requesting permission for the requesting wireless node to operate in a power save mode, the request message associated with a timer, a value of the timer being previously provided.

38. The method of claim 33 and further comprising using the new forwarding path to forward data.

39. The method of claim 33 wherein the determining comprises calculating a new forwarding path that does not include the requesting wireless node.

40. The method of claim 33 wherein the determining comprises: requesting a new forwarding path from one or more other wireless nodes; and receiving the new forwarding path.

41. The method of claim 33 wherein the determining comprises determining a new forwarding path that replaces the requesting wireless node with another wireless node.